Nuclear Genitourinary Studies

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Nuclear Genitourinary Studies

Vesicoureteral Reflux Study

abnormal

activity in upper urinary tracts during filling, at full capacity, and/or while voiding

all or nearly all solution voided from bladder

no reflux visualized

Total bladder volume residual post void volume and bladder volume at initiation of reflux can be measured

residual bladder volume [ml]= voided volume [ml] x residual counts/min

Divided by max counts/min - residual counts/min

Voiding phase

measure urine output

deflate foley and have patient void

place patient sitting on potty chair with camera posterior

Take 120 second immediate post void static and record CPM

Filling phase

once bladder is full, take 120 second immediate statics of posterior and L/R posterior obliques

monitor p-scope for signs of reflux (any activity above the bladder)

if reflux is seen, record amount of saline was infused at that time

fill until drip slows or voids around catheter

fill bladder to max capacity (age + 2) x 30 =volume instill [ml]

inject tracer into tubing connected to bladder catheter

image 5 sec/frame for 60 seconds

Posterior

patient positioning

sitting or supine

bladder and kidneys in FOV

MOL: compartmental with flow of urine

Critical organ: bladder (18-27 mrads/mCi)

indwelling bladder catheter

Dose: 0.5-1.0 mCi

Tc99m Sulfur Colloid

Tc99m pertechnetate

note amount of saline at start and finish

foley catheterization placement

inflate, balloon, tape to secure

aseptic technique

consent for catheterization

void prior to exam

Explain procedure to patient

Evaluation and detection of vesicoureteral reflux (VUR)

Diuretic Renal Imaging

Pre void and post void images of kidney and bladder

Lasix

Administer over 1-2 minutes by IV at 20 minutes

note frame number at time of administration

Dynamic

1-2 minutes/frame 20-30 minutes

Flow

30 frames x 2 seconds/frame

Generate Time Activity Curve

See Functional Renal Imaging

Patient Prep

SAME AS FUNCTIONAL RENAL IMAGING

Hydronephrosis

Renal obstructive neuropathy

Dehydration

Interventional Pharmaceutical

Furosemide

Pediatric dose: 1 mg/kg (Max 40 mg)

Dose: 20-80mg I.V.

Morphological Renal Imaging

Differentiate column of Bertin from mass

uptake in the column of Bertin, but not in a mass caused by tumor

Acute pyelonephritis

single or multiple defects resulting in decreased uptake

equal distribution in each kidney

smooth renal contour

Static images

Posterior/ RAO/LAO/RPO/LPO with kidney in center of FOV

2 hours post injection

Images

Data Acquisition

140 keV, 20% winodw

500k counts for each image

5 images total

LFOV gamma camera

SPECT: single, dual or triple head

Pinhole collimator for cortical images

prone preferred

parallel hole collimator for differential calculation

Positioning

include kidneys and bladder

Well Hydrated

void before imaging

Tc9m GH Gluceptate

Permits visualization of renal blood flow and imaging of the renal cortex

Secreted by Glomerular filtration and tubular secretion

Renal clearance is approximately 50% at 3 hours

Must be stored in the refrigerator

Child: 200 uCi/kg

Adult: 10-15 mCi

Intravenous

Tc99m DMSA

Child: 50uCi/kg

Webster's rule for pediatric dose: [age + 1] / [Age + 7] x adult dose

Adult: 5 mCi

10 mCI will give a higher dosimetry dose, but gives better image quality due to increased counts

25-50% of dose is in kidney in 1 hour and increases with time

Approx 16% will be in the urine in 3 hours after inj.

Taken up by renal cortex (proximal convoluted tubule) MOL tubular binding

90% binds to plasma proteins, preventing significant glomerular filtration

Tc99m dimercaptosuccinic

7 RADS to the renal cortex

Highest patient radiation dose of all renal imaging agents

pregnancy

not an absolute, risk-to-benefit ratio must be considered

patient movement

Confirmation of suspected hypertrophied column of Bertin

Scarring from acute pyelonephritis

pyelonephritis is usually results from reflux of infected urine

Adema

Renal Scintigraphy with ACE Inhibitor

Kidney Function decrease

Time to Peak activity decrease

prolonged renal parenchymal transit

Decreased renal uptake in one or both kidneys

Processing

ROI's

Background subtraction

cortical regions of the kidneys

Renogram Curve Analysis

Full FOV

Single or dual head camera

Posterior imaging

Obtain pre-void and post-void images

suspected ureteral obstruction

Serial Dynamic images

1-2 minutes/frame

20-30 minutes

Flow: Dynamic Acquisition

2-4 seconds/frame

60-120 seconds

Monitor patients blood pressure before administration of ACE inhibitor and every 15 minutes after for 1 hour

monitoring for hypotension

I.V. placement

Void before imaging

Fasting

4 hours fasting

Interventional Pharmaceuticals

Enalapirlat

Dose: 40ug/kg

I.V. over 3-5 minutes

Captopril

Given 1 hour before injection of radiopharmaceutical

Dose: 50mg

Pediatric dose: 0.5 mg/kg

Maximum: 25mg

P.O.

Crushed and dissolved in water

Radiopharmaceuticals

Tc99m

Energy: 140 keV

Tc99m DTPA

Target Organ: Kindeys

Tc99m MAG-3

Critical Organ: Bladder Wall

Target Organ: Kidneys

Pediatric: 0.15 mCi/kg

Maximum: 4mCi

Minimum: 1mCi

Adult: 5-10 mCi I.V.

No ACE inhibitors onboard

No diuretics onboard

Renal Hypertension

Renal Artery Stenosis

High Blood Pressure of unknown origin

Functional Renal Imaging

Imaging

Results

Abnormal

asymmetric

retention of activity in the kidneys

Normal

reasonably symmetric

kidney activity peaking at 3-5 minutes and decreased to less than 50% by 20 minutes

Processing Images

Quantitative analysis - relative renal function

ROI's drawn around kidneys, abdominal aorta and background

Equipment

LEAP collimator

Full FOV for adults

Zoom FOV for pediatrics

Single or dual head gamma camera

Anterior imaging for renal transplants

Posterior imaging for native kidneys

Procedure

TOTAL TIME: 22 MINUTES

Post Void: Posterior static acquisition

2 minutes

Function: Dynamic acquisition

19 minutes of 20 s/frame; compressed to 1 min/frame

Flow: Dynamic acquisition

30 frames x 2 s/frame

Patient Positioning

Use dose to mark sternal notch in top 1/3 of image and bladder in bottom 1/3 of image. Use dose to ensure patients left and right sides are in the image

Supine

Patient Preparation

IV placement

Well hydrated

Bladder emptied immediately before imaging

Radiopharmaceutical

Energy

140 keV

Tc99m - MAG 3

Pediatric: 100 uCi/kg

Minimum 1 mCi

Functional, effective renal plasma flow agent

MOL: Tubular reabsorption/Glomerular filtration

Tc99m - DTPA

Target organ: Kidneys

Critical organ: Bladder

Dose

Pediatric: 200 uCi/kg

Minimum 2 mCi

Adult: 10-20 mCi

Functional glomerular agent

MOL: Glomerular filtration

Administration

Large antecubital vein preferred

Intravenous, bolus

Contraindications

Recent nuclear medicine studies

Pregnancy or breastfeeding

Indications

Postsurgical renal function assessment after pyeloplasty

Address renal function in infants with hydronephrosis

Assess for RAS or urinary reflux and scarring

Assess cause for acute renal failure or UPJ obstruction

Evaluate blood flow and function of renal transplant

Assess split renal function for native kidneys